1. Field
The present invention relates to a leak sensor capable of detecting a fluid leakage through side detection, and more particularly, to a leak sensor for side detection, which is in contact with a fluid dropping and flowing on a floor even though not located just under the leaked fluid and thus detects the fluid leakage.
2.Background
Generally, many chemical substances are used in a semiconductor manufacturing processes. For example, a cleaning solution which is used in a cleaning operation after cutting and polishing processes of a wafer, a photosensitive solution which is used in a photosensitive process of the wafer, a developing solution which is used in a developing process of the wafer, and an etching solution which is used in an etching process of the wafer, are used in the semiconductor manufacturing processes.
These chemical substances are transferred to in-situ positions for performing each of the processes through transfer pipes. The chemical substances may leak to an outside of the transfer pipes due to a defect or deterioration of the transfer pipes. Since the leaked chemical substances may have a bad influence on other devices or components in semiconductor manufacturing sites, it is necessary to detect a leak in the transfer pipes and to rapidly take a corresponding measure.
In a method of detecting the leakage in the transfer pipes, a positive (+) electrical wire and a negative (−) electrical wire are disposed in parallel, and an absorbent is disposed between the wires, and a change in resistance occurring by the leaked chemical substances is measured. A sensor using such a method is referred to as a line type leak sensor.
Here, in a leakage detection method of the line type leak sensor, the positive (+) wire (or electric conductor) and the negative (−) wire (or electric conductor) are disposed at a drain which extends from the transfer pipe and collects the chemical substances leaked from the transfer pipes, and thus whether leakage occurs is measured. An example of the line type leak sensor is disclosed in Korean Patent Application Publication No.10-2007-005234.
Meanwhile, there is an area type leak sensor which has a wider leakage detection area than the line type leak sensor. The area type leak sensor forms a predetermined detection area by arranging a plurality of (+) conductor wires and (−) conductor wires to cross each other or arranging one pair of (+) conductor wire and (−) conductor wire in a zigzag pattern. An example of such an area type leak sensor is disclosed in Japanese Patent Application Publication No. 1989-171340.
Here, the area type leak sensor is in contact with a leaked fluid which falls down, and thus can detect fluid leakage. However, in such a detection method, the leak sensor should be directly disposed under portions at which the occurrence of leakage is expected, and when the leaked fluid does not fall down on an upper surface of the leak sensor, there is a problem that the leak cannot be detected. That is, the conventional area type leak sensor has a problem that the occurrence of the leak cannot be detected unless the fluid which leaks and flows on a floor corresponds to the amount sufficient to reach said upper surface of the leak sensor, except the case in which the leak sensor is located just under a leak position of the fluid.